Whey Protein Consumption Research Articles

Effect of premeal consumption of whey protein and its hydrolysate on food intake and postmeal glycemia and insulin responses in young adults

Dairy protein ingestion before a meal reduces food intake and, when consumed with carbohydrate, reduces blood glucose. The objective was to describe the effect of whey protein (WP) or its hydrolysate (WPH) when consumed before a meal on food intake, pre- and postmeal satiety, and concentrations of blood glucose and insulin in healthy young adults. Two randomized crossover studies were conducted. WP (10-40 g) in 300 mL water was provided in experiment 1, and WP (5-40 g) and WPH (10 g) in 300 mL water were provided in experiment 2. At 30 min after consumption, the subjects were fed an ad libitum pizza meal (experiment 1) or a preset pizza meal (12 kcal/kg, experiment 2). Satiety, blood glucose, and insulin were measured at baseline and at intervals both before and after the meals. In experiment 1, 20-40 g WP suppressed food intake (P < 0.0001) and 10-40 g WP reduced postmeal blood glucose concentrations and the area under the curve (AUC) (P < 0.05). In experiment 2, 10-40 g WP, but not WPH, reduced postmeal blood glucose AUC and insulin AUC in a dose-dependent manner (P < 0.05). The ratio of cumulative blood glucose to insulin AUCs (0-170 min) was reduced by > or =10 g WP but not by 10 g WPH. WP consumed before a meal reduces food intake, postmeal blood glucose and insulin, and the ratio of cumulative blood glucose to insulin AUCs in a dose-dependent manner. Intact WP, but not WPH, contributes to blood glucose control by both insulin-dependent and insulin-independent mechanisms. This trial was registered at clinicaltrials.gov as NCT00988377 and NCT00988182.

The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes

The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes

Influência das proteínas do soro sobre enzimas hepáticas, perfil lipídico e formação óssea de ratos hipercolesterolêmicos

OBJETIVO: Avaliar o efeito do consumo das proteínas do soro do leite sobre parâmetros do metabolismo lipídico, hepático e renal, a formação óssea e as defesas antioxidantes de ratos submetidos à dieta hipercolesterolemiante. MÉTODOS: Trinta e dois ratos Fisher adultos foram divididos em 4 grupos, recebendo as seguintes dietas: grupo C, dieta padrão; grupo H, dieta hipercolesterolemiante; grupo PS, dieta padrão e proteínas do soro; grupo PSH dieta hipercolesterolemiante e proteínas do soro. A ingestão alimentar e o ganho de peso foram monitorados semanalmente. Após 8 semanas, o sangue dos animais foi coletado para dosagem bioquímica e os animais foram eutanasiados. Foram utilizados os testes estatísticos, análise de variância e o teste de Tukey. RESULTADOS: As proteínas do soro não reduziram o colesterol plasmático de forma significante, e promoveram um aumento na concentração plasmática de triacilgliceróis nos animais hipercolesterolêmicos. No entanto, reduziram a atividade da aspartato aminotransferase e da fosfatase alcalina, assim como a concentração plasmática de creatinina. Não se observou nenhum efeito sobre as defesas antioxidantes avaliadas. As dietas contendo as proteínas do soro geraram ossos mais pesados, com maior diâmetro e comprimento que as dietas contendo caseína. CONCLUSÃO: As proteínas do soro não apresentaram um efeito hipocolesterolemiante significante em ratos. No entanto, impediram de forma significante a ocorrência de alterações nos parâmetros indicadores das funções hepáticas e renais provocadas pela dieta hipercolesterolemiante. Os dados sugerem também que as proteínas do soro afetam positivamente a formação óssea, quando comparados com as dietas contendo caseína como fonte protéica.

Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in trained young men

Whey protein is a supplemental protein source often used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post-exercise period. Eight healthy resistance-trained young men (age=21+/-1 .0 years; BMI=26.8+/-0.9 kg/m2 (means+/-SE)) participated in a double-blind randomized crossover trial in which they performed a unilateral leg resistance exercise workout (EX: 4 sets of knee extensions and 4 sets of leg press; 8-10 repetitions/set; 80% of maximal), such that one leg was not exercised and acted as a rested (RE) comparator. After exercise, subjects consumed either an isoenergetic whey protein plus carbohydrate beverage (WHEY: 10 g protein and 21 g fructose) or a carbohydrate-only beverage (CHO: 21 g fructose and 10 g maltodextran). Subjects received pulse-tracer injections of L-[ring-2H5]phenylalanine and L-[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS in the WHEY-EX and CHO-EX legs, which were greater than MPS in the WHEY-RE leg and the CHO-RE leg (all p<0.05), respectively. The rate of MPS in the WHEY-EX leg was greater than in the CHO-EX leg (p<0.001). We conclude that a small dose (10 g) of whey protein with carbohydrate (21 g) can stimulate a rise in MPS after resistance exercise in trained young men that would be supportive of a positive net protein balance, which, over time, would lead to hypertrophy.

Appetite hormones and energy intake in obese men after consumption of fructose, glucose and whey protein beverages

To investigate appetite responses over 4 h to fructose beverages in obese men, relative to glucose and whey protein. Second, to investigate the effect of combining whey and fructose on postprandial appetite hormones. Randomized, double-blind crossover study of four beverages (1.1 MJ) containing 50 g of whey, fructose, glucose or 25 g whey+25 g fructose. Blood samples and appetite ratings were collected for 4 h then a buffet meal was offered. Twenty-eight obese men (age: 57.0+/-1.6 years, body mass index: 32.5+/-0.6 kg/m(2)). Plasma ghrelin (total), glucagon-like peptide-1 (GLP-1 7-36), cholecystokinin-8, glucose, insulin and appetite ratings were assessed at baseline and 30, 45, 60, 90, 120, 180, 240 min after beverages, followed by measurement of ad libitum energy intake. Fructose produced lower glycaemia and insulinaemia compared to the glucose treatment (P<0.0001); whereas postprandial ghrelin, GLP-1 and cholecystokinin responses were similar after both treatments. Whey protein produced a prolonged (2-4 h) suppression of ghrelin (P=0.001) and elevation of GLP-1 (P=0.002) and cholecystokinin (P=0.003) that were reduced when combined with fructose, while glucose and insulin responses were similar. Energy intake after 4 h was independent of beverage type (glucose 4.7+/-0.2 MJ; fructose 4.9+/-0.3 MJ; whey 4.6+/-0.3 MJ; whey/fructose 4.8+/-0.3 MJ; P>0.05). In obese men, fructose- and glucose-based beverages had similar effects on appetite and associated regulatory hormones, independent of the differing glycaemic and insulinaemic responses. The contrasting profile of plasma ghrelin, GLP-1 and cholecystokinin after whey protein consumption did not impact on ad libitum intake 4 h later and was attenuated when 50% of whey was replaced with fructose.

Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in young men.

Whey protein is a supplemental protein source used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post-exercise period. Eight healthy young men (BMI = 26.8±0.9; age = 21±1) participated in a double-blind randomized cross-over trial in which they performed a unilateral leg resistance exercise workout – EX – (4 sets of knee extensions and 4 sets of leg press – 8–10 reps per set), such that the other leg was not exercised and acted as a rested (RE) comparator. After exercise subjects consumed either an isocaloric whey protein plus carbohydrate beverage (10g whey and 21g fructose) – WHEY – or a carbohydrate beverage containing fructose and maltodextrin (21g and 10g, respectively) – CHO. Subjects received pulse-tracer injections of L[ring-2H5]phenylalanine and L-[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS only in the WHEY-EX leg, which was greater than MPS in the WHEY-RE leg and also the CHO-EX leg (all P<0.01). We conclude that a small dose (10g) of whey protein with carbohydrate (21g) can stimulate a rise in MPS after resistance exercise which, overtime, would be supportive of a net muscle protein accrual and hypertrophy. Supported by the US National Dairy Council.

Dietary exposure to soy or whey proteins alters colonic global gene expression profiles during rat colon tumorigenesis

BackgroundWe previously reported that lifetime consumption of soy proteins or whey proteins reduced the incidence of azoxymethane (AOM)-induced colon tumors in rats. To obtain insights into these effects, global gene expression profiles of colons from rats with lifetime ingestion of casein (CAS, control diet), soy protein isolate (SPI), and whey protein hydrolysate (WPH) diets were determined.ResultsMale Sprague Dawley rats, fed one of the three purified diets, were studied at 40 weeks after AOM injection and when tumors had developed in some animals of each group. Total RNA, purified from non-tumor tissue within the proximal half of each colon, was used to prepare biotinylated probes, which were hybridized to Affymetrix RG_U34A rat microarrays containing probes sets for 8799 rat genes. Microarray data were analyzed using DMT (Affymetrix), SAM (Stanford) and pair-wise comparisons. Differentially expressed genes (SPI and/or WPH vs. CAS) were found. We identified 31 induced and 49 repressed genes in the proximal colons of the SPI-fed group and 44 induced and 119 repressed genes in the proximal colons of the WPH-fed group, relative to CAS. Hierarchical clustering identified the co-induction or co-repression of multiple genes by SPI and WPH. The differential expression of I-FABP (2.92-, 3.97-fold down-regulated in SPI and WPH fed rats; P = 0.023, P = 0.01, respectively), cyclin D1 (1.61-, 2.42-fold down-regulated in SPI and WPH fed rats; P = 0.033, P = 0.001, respectively), and the c-neu proto-oncogene (2.46-, 4.10-fold down-regulated in SPI and WPH fed rats; P < 0.001, P < 0.001, respectively) mRNAs were confirmed by real-time quantitative RT-PCR. SPI and WPH affected colonic neuro-endocrine gene expression: peptide YY (PYY) and glucagon mRNAs were down-regulated in WPH fed rats, whereas somatostatin mRNA and corresponding circulating protein levels, were enhanced by SPI and WPH.ConclusionsThe identification of transcripts co- or differentially-regulated by SPI and WPH diets suggests common as well as unique anti-tumorigenesis mechanisms of action which may involve growth factor, neuroendocrine and immune system genes. SPI and WPH induction of somatostatin, a known anti-proliferative agent for colon cancer cells, would inhibit tumorigenesis.

Whey Protein Concentrates With and Without Immunoglobulins: A Review

ABSTRACT Whey protein, a high-biological-value protein from milk, is available with and without immunoglobulins. The possibility of providing passive immunization through food is unique to mammals, who receive it through colostrum at birth. Colostrum contains both immunostimulatory and immunosuppressive immunoglobulins. Later, the mammals are able to make their own immunoglobulins, but in time of illness that ability may become impaired. Some of the whey proteins contain bovine immunoglobulins, which are similar to human immunoglobulins. This type of whey may be of clinical importance to patients who are immunocompromised. However, all whey proteins are rich in cysteine and glutamate. These serve as precursors of glutathione, a potent antioxidant, which is needed in greater quantities during stress. In this review, the benefits of consuming whey protein with and without immunoglobulins are examined. Characteristics of these products are discussed, and an account is given of supportive studies using the whey containing immunoglobulins in the clinical setting. Patients with acquired immunodeficiency syndrome and cancer are used as examples. Finally, a guide on use of whey protein is provided.